Paperboard rim for knock-down paperboard containers



April l2, 1955 J. c. LA GRUA x-:rAL 2,706,074

PAPERBOARD RIM FOR KNOCK-DOWN PAPERBOARD CONTAINERS Filed OGl.. 21, 1952 l] IIIiIII "lll l v2l L3A l M 'MIM-I ATTORNEY Unite l PAPERBARD RIM FOR KNOCK-DOWN PAPERBOARD CONTAINERS James C. La Grita, Pine rchard, and Edward G.

Mathews, Guilford, Conn., assignors, by mesne assignments, to National Folding 150x Company, Incorporated, New Haven, Conn., a corporation of New York Application October 21, 1952, Serial No. 315,932 3 Claims. (Cl. 229-5.7)

States Patent C) and end closure disks which are fastened to the wall i member by suitable rims. The wall member generally is scored so that it can be collapsed and stored in a minimum of space. The wall member is readily ex* panded, generally into `cylindrical form, and is fitted with end disks which then become the bottom and also the cover of the container.

According to conventional practice the wall member is equipped with terminal lianges for engagement by metal rims. These flanges are formed by folding and gluing a marginal strip of board back upon the wall.

Two different types of metal rims are commonly used to attach the end disks. The bottom rim is of substantially L-shaped cross section, and the top rim is of substantially l-shaped cross section, the vertical end of the L and both ends of the I being curved in semi-bead fashion towards the inside of the rim. The semi-beaded edges of the rims engage the flanges on the wall and the horizontal L portion of the bottom rim supports a bottom disk.

The conventional rims are made from corrosion resistant steel. Special machinery is required for making them, and their cost is relatively high. In addition, the users of paperboard containers of the aforementioned type, for example the ice cream industry, is dependent for the supply of containers not only on the availability of paperboard which usually is available, even in times of material shortage, but also on the availability of steel or other metal, and the ability of sheet metal manufacturers to produce rims. There are periods of time when steel is in short supply and other periods when production is interrupted by other causes.

To eliminate the dependence on metal, attempts have been made from time to time to substitute paperboard rims for the metal rims. These attempts, as far as we are aware, have not been successful particularly not for ice cream containers which must meet several exacting requirements.

Firstly, the container must permit shipping and storage in iiat collapsed condition.

Secondly, the container must be simple to assemble, and, when assembled, must be liuid tight.

Thirdly, the container must not come apart when its contents expand during freezing.

Metal rims resist the forces of expansion successfully, and moreover the horizontal portion of the bottom rim of L-shaped cross section is so wide that the bottom disk is securely held, even if the rate of expansion is conside-table.

Paperboard does not lend itself to the formation of a similarly shaped support for the container bottom and` its attempted substitution for the metal rims has therefore met with dilliculties.

The present invention provides an improved construction for paperboard rims which has proved highly dependable and successful. According to the invention the paperboard rim is provided with an extremely stiff supporting area for engagement by the container bottom, the width of the area being considerably larger than the thickness of the board and suicient to support the bottom disk positively, even if the diameter of the rim is ICC expanded by freezing by an amount equal to twice the thickness of the paperboard.

These and other features, objects and advantages of the invention will appear more fully from the detailed description which follows, accompanied by drawings, showing for the purpose of illustration, a preferred embodiment of the invention. The invention also resides in certain new and original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of the invention which are believed to be novel Will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages, and the manner in whcih it may be carried out, may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part of it, in which:

Fig. 1 is a plan view of a at blank from which a rim embodying the invention may be made;

Fig. 2 is a perspective view of the completed rim;

Fig. 3 is a section taken in plane 3 3 of Fig. 2 on an enlarged scale;

Fig. 4 is an elevational cross section through a paperboard container, including the rim of Fig. 2; and

Fig. 5 is a view of the left lower portion of Fig. 4 on an enlarged scale.

ln the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be as generic in their application as the art will permit. Corresponding reference characters refer to corresponding parts in ,the several figures of the drawing.

ln the drawings accompanying, and forming part of this specification, certain specific disclosure of the invention is made for the purpose of explanation of broader aspects of the invention, but it is understood that the details may be modified in various respects without departure from the principles of the invention, and that the invention may be embodied in other structures than the one shown.

The blank A shown in Fig. l may be cut and scored from large sheets or rolls of paperboard on automatic cutting and scoring machines. The blank may be of the same thickness and of the same stock as the walls of the paperboard container.

rhe blank A comprises a main or body portion 11 to which marginal strips 12 and 13 are articulated along fold lines 14 and 15. These fold lines may be cut scores extending part way, but not entirely through, the stock. The marginal strips 12 and 13 are preferably somewhat shorter than the main body portion, so that the body portion 11 extends beyond the ends of the marginal strips at 16 and 17. The portions 16 and 17 constitute securing portions for connecting the ends of the blank together to form a rim, as will presently become apparent.

Substantially U-shaped cuts 18 extend through the blank at various places. These cuts preferably terminate at fold lines 19 and form lugs 20. The dimensions are preferably so selected that the distance D from the fold line 19 to the bight of the U is greater than twice the thickness of the board. For ice cream cans of the 21/2 gallon size, the dimension D may range from 5%6 of an inch to about 7/i6 of an inch. The'smaller dimensions within this range are qu-ite satisfactory from a structural point of View and have the advantage of being inconspicuous. The fold lines 19 are spaced from the fold line 15, a distance d substantially equal to the width w of thev marginal strip 13. If these dimensions are observed, the outer edge 21 of the marginal strip 13 will line up with the fold lines 19 if the marginal strip 13 is folded back upon the main body portion 11.

It is not absolutely necessary to provide fold lines 19. These fold lines can be omitted. ln that event it is preferable to have the ends of the U-shaped cuts 18 extend to within a distance from the fold line 15 equal to the width w of the marginal strip 13.

The blank A may be converted into rim form as follows:

The blank A is rst folded along the fold lines 14 and 1S to fold the marginal strips back upon the main body portion of the blank from which they extend. Preferably, the marginal strips are secured to the blank in folded back position. This may be done by applying adhesive to the marginal strips, or by putting metal stitches through the two thicknesses of the board after folding. If adhesive is used, it should be of the waterproof type. Such adhesive is commonly used in the manufacture of paperboard containers for ice cream.

The ends of the blank are then joined by overlapping the securing portion 16 and 17. The overlapping portions may be connected together by gluing or by driving a staple therethrough as indicated at 22. The folded blank is so curved that the folded-over marginal strips lie on the inside of the rim.

Before or after formation of the blank A into rim form, but preferably after the folding of the marginal strips, the lugs 20 are folded at right angles with respect to the main body portion. This is illustrated at Fig. 3 on an enlarged scale. It is seen that in deflected position the lugs rest upon the outer edge 21 of the marginal strip 13 and protrude a certain distance beyond the strip 13.

The rim A', as illustrated in Fig. 2, is now ready for assembly with the other elements of the container. Referring to Fig. 4, the container consists of a tubular wall 23 having turned back marginal portions 24 and 25. The marginal portions 24 and 25 lie on the outside of the wall 23 and are preferably secured to the wall by waterproof adhesive in accordance with conventional practice. T he terminal edges of the turned-back portions form flange surfaces 26 and 27.

The assembly of the container may proceed as fol- :A

lows:

The rim A is placed on a flat surface and a flat outer bottom disk 28 is placed into the rim so that the disk rests on the interned lugs 20 and on the edge 2l.

A cylindrical wall blank 23 is then inserted into the rim by distorting the wall blank sufficiently from its cylindrical shape that it moves past the upper flange of the rim formed by the turned-back marginal strip 12. The wall blank 23 is then positively expanded into cylindrical form which is suitably accomplished by forcing an inner bottom disk 29 into it. This inner bottom disk 29 expands the bottom portion of the wall 23 and presses it firmly against the rim A.

From Fig. it will be observed that the distance from the upper surface of the lugs to the downwardly facing edge 30 of the marginal strip 12 is substantially equal to the distance from the upwardly facing edge 27 of the wall structure to the bottom edge 31 of the wall structure plus the thickness of the outer bottom disk 28. A slight amount of play between the edges 27 and 30 is not harmful but facilitates assembly of the container.

The set-up container is now ready for filling with contents, for example with ice cream. The snug t of the inner bottom disk 29 against the inner surface of the wall blank 23 insures Huid-tightness. During freezing the contents of the container expand somewhat and may enlarge the diameter of the wall slightly. Simultaneously, the rim A is expanded to the same extent. However, the diameter of the disks 28 and 29 does not increase. After freezing the problem of leakage does not exist since the contents are no longer fluid. However, it is necessary to insure that the bottom of the container does not drop out or, what amounts to the same, that the rim A will not slide up the wall 23. It is easily seen that this is likely to happen, if the outer bottom disk 28 were solely supported on the edge 21, and if the diameter of the rim, due to expansion by freezing, is increased by more than twice the thickness of the paperboard.

The lugs 20 prevent such disengagement of the bottom structure and hold the bottom disc securely in place. The lugs 20 derive their stiffness from the fact that they rest upon the upper edge 21 of the marginal portion 13. In that respect the lugs 20 differ from similar lugs punched out from metal rims. We are aware that metal rims have been used, in which U-shaped lugs are formed. These lugs were bent over a paperboard top disk for the purpose of holding the disk in place. In the known construction the top disk is solely held by the resistance of the lugs to bending back into their original position.

Paperboard lugs cannot be employed in a similar manner and the lugs employed by the present invention are acted upon in a direction to move the lugs not towards the position from which they were deflected, but further away. The resistance of the lugs to such movement is not the resistance which the lugs offer, due to their stiffness, to further folding about their original fold lines, but the lugs are positively supported by a ledge 21 not present in the aforementioned sheet metal version. The support of the ledge imparts great stiffness and strength to the lugs 20, amply sufficient to prevent disengagement of the bottom assembly.

The invention thus provides a relatively simple and inexpensive form of rim which has proved highly satisfactory.

What is claimed is:

l. An improved rim for knock-down containers of paperboard of the type comprising a cylindrical wall, end closure disks, and securing rims for securing the disks to the wall, the rim consisting of a strip of paperboard, said strip including a body portion and marginal portions along the long edges of the body portion, said marginal portions being folded back upon said body portion, whereby the edges of the marginal portions form supporting ledges, the ends of the strip being secured together to form an endless rim, said body portion having lugs cut therefrom, said lugs being bordered by cut lines terminating at points adjacent one of said supporting ledges and being foldable over said one supporting ledge toward the inside of the rim into substantially right angular position with regard to said body portion in which position said lugs bear upon said one ledge, and extend beyond said one ledge, thereby increasing the supporting surface of the rim at said ledge to a dimension greater than the thickness of the board from which the rim is made.

2. An improved rim for knock-down containers of peperboard of the type comprising a cylindrical wall, end closure disks, and securing rims for securing the disks to the wall, the rim consisting of a strip of paperboard, said strip including a body portion and marginal portions along the long edges of the body portion, said marginal portions being folded back upon, and secured to, said body portion, whereby the edges of the marginal portions form supporting ledges, the ends of the strip being secured together to form an endless rim, said body portion having lugs cut therefrom, said lugs being bordered by cut lines terminating at points adjacent one of said supporting ledges and having a fold line substantially in line with said one supporting ledge, thereby being foldable over said one supporting ledge toward the inside of the rim into substantially right angular position with regard to said body portion in which position said lugs bear upon said one ledge, and extend beyond said one ledge, thereby increasing the supporting surface of the rim at said ledge to a dimension greater than the thickness of the board from which the rim is made.

3. An improved rim for knock-down containers of paperboard of the type comprising a cylindrical wall, end closure disks, and securing rims for securing the disks to the wall, the rim consisting of a strip of paperboard, said strip including a body portion and marginal portions along the long edges of the body portion, said marginal portions being folded back upon, and secured to, said body portion, whereby the edges of the marginal portions form supporting ledges, the ends of the strip being secured together to form an endless rim inA which said marginal portions lie on the inside, said body portion having lugs cut therefrom, said lugs being bordered by a substantially straight fold line substantially in line with one of said supporting ledges and by a substantially U-shaped cut line terminating at the ends of said fold line, said fold line permitting folding of the lug over said one ledge toward the inside of the rim into substantially right-angular position with regard to said body portion, the distance from the fold line to the bight of the U being greater than the thickness of the board from which the rim is made, said lugs in the position in which they bear upon said one ledge forming a stiff supporting area for a closure disk, the radial extent of the supporting area being larger than the radial extent of the area afforded by the thickness of the board at said ledge.

References Cited in the file of this patent UNITED STATES PATENTS 1,866,496 Witte July 5, 1932 2,181,545 Boothby et al. Nov. 28, 1939 2,346,685 Hothersall Apr. 18, 1944 

